1. FIELD OF THE INVENTION
This invention relates to an engine control apparatus and, more particularly, it is concerned with an engine control apparatus which is capable of detecting misfire in any of the engine cylinders, and preventing unburnt gas in the misfired cylinder from burning in the vicinity of the exhaust pipe to shorten the service life of a catalyst in the exhaust pipe. In this application, misfire is used in the sense of the absence of an ignition signal, which is the main cause of non-ignition.
2. DISCUSSION OF BACKGROUND
Some of the conventional engine control apparatus carry out their fuel injection control and the ignition control for each engine cylinder. In such engine control apparatus, a multi-point injection device is used for the fuel injection control, while a low-tension power distribution ignition device is used for the ignition control.
In the above-described conventional engine control apparatus, the engine operation can still be continued, even if misfire occurs in a particular engine cylinder. However, when unburnt gas is discharged from the misfired cylinder, it is burned in the vicinity of the exhaust pipe to heat even a catalyst filled in it. On account of this, not only the service life of the catalyst becomes shortened, but also there is apprehension such that fire could occur.